Since various kinds of information are required for controlling a motor vehicle, it is proposed to provide a sensor device to a hub unit (rolling bearing) having a fixed side raceway member fixed to the body side, a rotational side raceway member to which a wheel is mounted, and two rows of rolling elements disposed between the both members. For example Patent Document 1 (Publication of Japanese Patent Application Laid-Open No. 2004-45370) discloses an invention in which a magnetic impedance sensor is provided to a fixed side raceway member and a ring-shaped magnetized part facing the sensor is provided to a rotational side raceway member so as to calculate a ground contact load with high accuracy.
According to the rolling bearing device with a sensor of Patent Document 1, detection by the magnetic impedance sensor is affected by the material, shape and processing accuracy of a detected part, so there have been problems that selection of a material of a rolling bearing involves restrictions, and processing or a magnetized part and addition of another member are required in a detected part.